In a few of the cases there wasn't, but I distinctly recall reading that the ATF said the "marks" or "markings" on the bullet were a match in the Monday shooting and some of the others.
Joe Riehl, assistant director of the Baltimore office of the federal Bureau of Alcohol, Tobacco and Firearms, said he would not comment on whether any shell casings had been found at the scene or what other evidence had been collected. After ballistics tests were conducted on fragments of the bullet that struck the Bowie boy, Riehl said the projectile was "identical to those" in previous attacks, in which the assailant used a high-powered .223-caliber rifle. "What we're saying is that the evidence here is the same as the evidence recovered there," Riehl said.
Chief Moose said: "The shooting this morning in Prince George's County is linked. The ballistics, the evidence, the science tells us that."
Authorities, citing ballistics tests, have said that the same rifle was used in three of the Montgomery killings, the D.C. slaying and the shooting in Spotsylvania. The bullet fragments from the other two Montgomery slayings could not be accurately tested.
To me "the same rifle" meant a bullet match. OTOH, prior to this incident I'd read and thought that doing that kind of match on a high velocity rifle bullet was more than merely problematic. I could buy "the same kind of rifle", but considering how beat up and fragmented the bullets likely are, I though "the same rifle" to be a bit strong.
If the evidence really only supports the same kind or even more weakly the same caliber, then I would say that the Monday shooting was a copycat, but not a very good one. Different technique, left behind brass, and the tarot card, all different from the other shootings.
OTOH, maybe there were tarot cards at some or all of the other shootings, and we just didn't find out about it, since the police (probably) didn't want the information known on this one.